Telephone system.



H. P. GLAUSEN.

TELEPHONE SYSTEM.

(Application filed Apr. .28, 1901.)

No. 70:,152. Patented ma 27, 1902.

( n Mqdel.)

-1'Hr: NORRIS Firms cn Pwovoumuu WASHINGTON, o. c.

NTED STATES 'ATEENT OFFICE.

HENRY P. CLAUSEN, OF CHICAGO, ILLINOIS, ASSIGNOR' TO AMERICAN ELEC- TRIC TELEPHONE COMPANY, A CORPORATION OF NEV JERSEY.

TELEPHONE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 701,152, dated May 27', 1902.

Application filed April 26, 1901. Serial No. 57,530. (No model.) i

To aZZ whom, it IN/(6y concern:

Be it known that I, HENRY P. CLAUSEN, a citizen of the United States of America, and a resident of Chicago, Cook county, Illinois,

have invented a certain-new and useful Improvement in Telephone Systems, of which the following is a specification.

My invention relates to improvements in telephone systems, and more especially to 1o those systems having a central office at which subscribers lines terminate, with means at such office to manually connect the lines together for conversational purposes, together with apparatus for completely supervising connections and performing all other necessary operations.

The object of my inventionis the simplification of systems of the class described, to reduce the labor of the operators at the cenzo tral oflice in making and taking down connections, to furnish a complete supervisory system of signals for established connections, as well as a means of automatic signaling from the substations to the central office, and,

in general, to provide an efficient and economical system throughout.

To the accomplishment of these and such other objects as may hereinafter appear, the invention consists in a system in which the subscribers stations are provided with the usual apparatus and in which the calling of the central office and the clearing-out signal are accomplished by merely taking up and replacing the receiver. A grounded signalingbell is also provided at the stations, which may be a low-Wound bell, if preferred, and therefore cheap. The central office equipment comprises cord-circuits having the tips and sleeves of the plugs connected by the cord-strands. Relays are bridged across the strands with the middle point of the bridge connected with the common battery, which also operates the line-signals. Each such relay is subservient to the operation of the corresponding subscribers hook switch, and when operated gives a distinctive signal and further operates means to open the circuit to the other station to prevent the undesired operation of the other relay. Means are also provided to enable the operators to talk with the subscribers at all times.

The invention further consists in the novel arrangement and constructions hereinafter described, and particularly pointed out in the claims, reference being had to the accompanying drawings, forming apart hereof, in which the same reference characters indicate like parts throughout the several views, and in which- Figure l is a diagram of two subscribers stations in lines and the central office apparatus. Fig. 2 is a diagram in simplestform of two connected. substations. Fig. 3 is a diagram of a modification of the central office apparatus. I

In the figures, A and B designate subscribers stations where the usual apparatus is employed, including the transmitters 2, local batteries 3, induction-coils 4E, receivers 5, and telephone hook-switches 6, connected to one of the pair of line conductors and a signalbell 7 in agrounded branch from the normal or resting contact of the hook. The metal= lic lines comprising the conductors 8 and 9 extend to the central office, Wherethey connect with spring-jacks 10, having springs 11 and 12, which are normally'connected with the grounded branch 11', including the individual line-signal 13 and the lead 30 of the common battery 14,that is grounded, as shown 86 at G.

The operators connective means at the central station includes the cord-circuit, having the answering and connecting plugs 19 andp at each end thereof, the cord-strands l7 and 18 each extending from the tip-contact 19 of one plug to the sleeve-contact 20 of the other. The usual listening andringing key is provided and is indicated conventionally in the drawings, the spring 21 being adapted to cono nect the operators telephone with the cordcircuit and the springs 22 to similarly connect the grounded ringing generator 15 with the plug 19. The supervisory signals 23 and 24, which are preferably lamps, are associated with the respective ends or plugs of the cordcircuit and serve when a connection is established to indicate the condition of the telephone at the subscribers stations of the connected lines-that is, if the receivers are or,

are not upon their hooks. These signals are operated or controlled by relays 25 and 26,

located in a bridge or connection 16 across the cord-circuit, a point of which intermediate the said relays [is connected with the battery 14 by the branch conductor 14. These relays of course may be replaced by relays of other suitable form or character, each coil having an armature or other equivalent construction and arrangement. The

supervisory lamp circuits are extended through the front contacts and armatures of the relays 25 and 26 by conductors 28 and 24 to a common conductor 27, that includes the relays 28 and 29 and connects with the common battery-lead 30, the latter relays serving by their armatures and back contacts to open the cord-strands 17 and 18 at the points indicated.

In the operation of the system the subscriber A removeshis receiver from the hook, thus closing a circuit from ground G at central through the common battery 14, lead 30, line conductor 9, receiver 5, secondary of the induction-coil 4, through the hook, line-wire 8, conductor. 11, and line-signal 13 to ground and operating, his individual signal 13. The operator upon seeing the signal. exposed in serts. the plug 19 in the jack 10 of the subscriber calling and connects her telephone therewith by means of the springs 21 of the listening and ringing key. Upon learning the number of the wanted party she inserts the. calling-plug, p into the jack 10 of that subscriber and connects the ringing generator with that end of the plug-circuit by means of springs 22 of the ringing and listening key, which rings the subscribers bell over the grounded line conductor 8 and the tip-strand ground.

18 0f that end of the cord-circuit. When the answering-plug p was first inserted in the jack 10, thecorresponding relay 25 did not operate for the reason that the ground branch at, the subscribers' station was removed. and no completecircuit for the same was established with the hook; but as soon as the plug p was inserted a path for current from the battery 14 was provided through the, conductors 14 and 16, relay 26, cordstrandj18 to the tip-contact of the plug 19' to line-spring 11 of jack 10 and over line conductor 8 to station B, and thence through thetelephone hook-switch 6 and bell 7 to This suffices to operate the relay 26, lighting thelamp 24 associated with that end of the cord-circuit or plug 19', over a circnit from. the battery 14 through the common conductor or lead 30 to conductor 27 on, either side of the battery through branch conductor 24, armature, and front contact of relay 26 to supervisory lamp 24 and ground. Thissignalindicates to the operator that the subscriber has not yet responded to the call.

Thisflamp-circuit also includes in its parallel paths formed by conductor 27 the relays 28 and 29, which are at this time energifzed to attract their armatures and open the cord-strands 17 and 18 at the points shown, the said strands including the armatures and resting-contacts of said relays in the end por tions over which the relays 25 and 26 are not operated. The function for so opening the cord-strands on the other side of the bridge 16 from that over which the said relays are operated is to prevent the operation of the other relayin this case relay 25-over the cord-strand 17, line conductor 8, to the station A and back over'conductor 9, strand 18, to ground at station B, for this would have the effect of lighting supervisory signal 23 to the confusion of the operator; but the opening of the cord-circuit by means of the relay 28 prevents this undesired operation of the relay 25 over the metallic circuit and at the same time leaves intact the strand 17 from the bridge 16 to the plug 19, over which, together with line-wire 8, the relay 25 may be operated by current from battery 14 when the subscribers receiver is upon the book. This arrangement of circuits and action is illustrated more simply in Fig. 2, where the station A is shown with the hook-switch up and the station E with the hook-switch down. Under these conditions the path for current from the battery 14 will be from ground at the central station through the relay-coil 26 over the line-wire 8 to ground at station B. This will operate the corresponding supervisory signal; but if the circuit be not opened through to the other line A by the relay 28 a parallel path for current from the battery 14 will exist through the other relay 25, line-wire 8, to the station A, and back to the central office over the line-wire 9, where it joins the current already upon the conductor 8 and passes to ground at the station E. This would operate the relay 25 and, as explained, this is undesirable. To prevent this, the relays 28 and 29 are provided, which serve, whenever one of the bridged relays is energized, to open the metallic circuit to the other line and at the same time leave intact a circuit over which such line-signal can be controlled. When. the wanted subscriber responds to the signal, the ground is cut ofi thereat and the relay 26 is deenergized to extinguish the lamp 24. At the termination of the conversation both receivers are returned totheir hooks and both lamps are lighted, whereupon the operator withdrawsthe plugs and all parts are restored to normal position.

While in Fig. 1 I have shown relays 28 and 29 joined by the common wire 27 and both operated whenever either relay 25 or 26 is energized, it is notv necessary to the successful operation of my invetion that both said relays be operated at the same time, since it is only necessary to operate the relay associated with one end of the circuit when only the supervisory lamp associated with the other end of the circuit-is operated. An arrangement of circuits whereby this is accomplished is shown in Fig. 3, (the corresponding parts being designated as before,) wherein the relays 28 and 29 are shown in separate branches 27 and 27 with their corresponding lamps 23 and 24, the continuity of the circuits of which are controlled by the relays and 26, the latter being interchanged in the diagram. When in this arrangement the relay 26 is operated by the substation B, thecorresponding lamp 24 is lighted and the relay 28 is operated to open the other end of the cord-circuit. A similar operation takes place with reference to the relay 25 and station A. For convenience and simplification, however, I prefer the arrangement shown in Fig. 1, as it-is not objectionable to operate both relays 28 and 29 simultaneously.

In order to provide means for the operator to communicate with either station A or B whenever the relay 28 or 29 is energized, I

. bridge the break produced thereby by means of condensers 40, as shown in Fig. 1, which allows the operator to converse with either station, even though the strand thereto is opened by the relay-armatures. If preferred, high resistances 41, as shown in Fig. 2, may be used in place of the condensers; but they should be comparatively high-about five thousand ohms-in order to not defeat the very object of openingthe circuit by the relays.

It will be observed that this system embodies all the advantages of a common battery system, so far as signaling the central oflice from the subscribers stations and complete supervision of all connections are concerned, and in addition those of a through talkingcircuit without the inconvenience usually incident to arrangements of this character. In addition low-wound bells may be used for the substations and other advantages gained; Other suitable generators maybe used in place of the storage batteries 14. A common return-conductor may replace the ground connection. The proper dimensions of the electrical parts are obvious to those skilled in the art to which the invention appertains, and are accordingly not herein stated.

For the above-described operation it will be observed that the hook-switches must be connected with the line-wires in the same unvarying relation, the wires to the jacks with similar precision, and the strands of the cordcircuits should extend between tip and sleeve contacts of the plugs. Other relations may exist and still be operative, and I do not wish to be considered as holding that the improvement in all its features and aspects is limited to that shown and described.

While I have described the invention with reference to the various details of construction and arrangement, I do not wish to be limited thereto, as various changes, alterations, and modifications may be made therein ive meansat the central oflice to variously connect said lines together for conversational purposes, supervisory signals associated with said means to indicate the condition of the telephones at the connected subscribers stations, and a circuit-breaking device adapted to open the circuit to one station when the supervisory signal assigned to the other is operated.

2. In a telephone system, the combination with subscribers lines, of a central office at which the lines terminate, operators connective means at the central office to variously connect said lines together for conversational purposes, subscribers stations having telephones and hooks, and circuit-breaking device adapted to open the circuit to one of two connected subscribers when the telephone of one subscriber is off the hook and the telephone of the other subscriber is upon the hook.

3. In a telephone system, the combination with subscribers lines, of a central oiiice at which the lines terminate, operators connective means at the central office to variously connect said lines together for conversational purposes, subscribers stations being provided with telephones and hooks, and a relay.

and circuit connections adapted to open the circuit to a connected subscriber when his telephone is off the hook and the other subscribers telephone is upon the hook.

4. In a telephone system, the combination with subscribers stations having receivers and hook-switches, metallic telephone-lines extending therefrom to a central office, operators connective circuits to connect said lines together for conversational purposes, and a relay adapted and arranged to open one side of the circuit of a connected subscriber when one subscribers receiver is oi the hook and the other subscribers receiver is upon the hook.

5. In a telephone system, the combination with subscribers stations having receivers and hook-switches, metallic telephone-lines extending therefrom to a central office, operators connective circuits to connect said lines together in pairs for conversational purposes, supervisory signals associated with said means to indicate the condition of the subscribers instruments when connected together, and a circuit-breaking device adapted and arranged to open the circuit to one connected subscriber when the supervisory signal assigned to the other is operated.

6. In a telephone system, the'combination with subscribers stations having receivers and hook-switches, metallic telephone-lines extending therefrom to a central office, operators connective circuits to connect said lines gether, said signals being operated over one side of the metallic circuits and ground, and

a relay'adapted and arranged to open the other? side of the circuit to one subscriber when the supervisory signal for the other subscriber is operated.

7. In a telephone system, the combination with metallic telephone-lines, subscribers stations having hook-switches connected to one line conductor and normally grounded, cord-circuits at the central office to interconnect said lines for conversational purposes, relays connected across the line, a common battery connected between said coils and ground,supervisory signals controlled by said relays, and relays arranged for automatically opening the metallic circuit of one connected line when the signal of the other is operated.

8; In a telephone system, the combination with metallic telephone-lines, subscribers stations having hook-switches connected to one line conductor and normally grounded, cord-circuits at the central offic'e to interconnect. said lines for conversational purposes, relays connected across the line, a common battery connected between said coils and ground,supervisory signals controlled by said relays,and circuit-breakin g devices controlled by said relays for opening the circuit to one station when the signal assigned to the other is operated.

9. In a telephone system, the combination with metallic telephone-lines, hook-switches at the subscribers stations connected to one line conductor in the same unvarying relation and normally grounded, cord-circuits to interconnect said lines for conversational purposes having their strands connected with tip and sleeve contacts of the plugs, circuitclosing relays bridged across the cord-circuits, a common battery connected between a point intermediate said relays and earth, supervisory signals controlled by said relays and associated respectively with the ends of the cord-circuit, and circuit-breaking relays also controlled by said circuit-closing relays to open either end of the cord-circuit when the signal associated with the other end is operated.

10. In a telephone system, the combination with metallic lines, hook-switches at the subscribers stations connected toone line conductor in the same unvarying relation and normally grounded, cord-circuits to interconnect said lines for conversational purposes having their strands connected with tip and sleeve contacts of the plugs, relays bridged across the cord-circuits, a common battery connected between a point intermediate said relays and earth, said relays being operated over the grounded line conductors and corresponding strands of the cord-circuit, supervisory signals associated with the ends of the 1 cord-circuit, and relays for opening the other strands of the cord-circuit, said latter relays beiu g operated when one subscribers receiver is upon the hook and the other subscribers receiver is ofl? the hook.

11. 'In a telephone system, the combination with metallic lines, hook-switches at the sub scribers stations connected to one line conductor in the same unvarying relation and normally grounded, a cord-circuit to inter connect said lines for conversational purposes, circuit-closing relays connected across the cord-circuit, a common battery connected between a point intermediate said relays and earth, supervisory signals controlled by said relays assigned to each end of the cordcircuit, circuit-breaking relays to open each end of the cord-circuit also controlled by said circuit-closing relays, and local circuits each including said battery and one of said circuit breaking relays, the circuit-breakin g relay at one end of the cord-circuit operating when the supervisory signal at the opposite end is operated.

12. In a telephone system, the combination with metallic telephone-lines, hook-switches at the substations connected in unvarying relation with one line conductor, signal-bells grounded by said hook-switches, a central office at which the lines terminate, individual signals at said office for said lines, a common battery to which said lines and signals are normally connected, an operators cord-circuit comprising plugs and strands between the tip of one plug and sleeve of the other, two circuit-closing relays in a bridge of the cord-circuit, the middle point of which bridge is connected with said battery, said relays being adapted to be operated over the grounded line conductors and corresponding strands of the cord-circuit when a connection is established, supervisory signals associated with said plugs and controlled by said relays, and circuit breaking relays to open the cordstrand on one side of the bridge when a circuit-closing relay is operated over the other strand on the other side.

13. In a telephone system, the combination with metallic telephone-lines, hook-switches at the substations connected in unvarying relation with one line conductor, signal-bells grounded by said hook-switches, a central ofi ice at which the lines terminate, individual signals at said office for said lines, a common battery to which said lines and signals are normally connected, an operators cord-circuit comprising plugs and strands between the tip of one plug and sleeve of the other, two circuit-closing relays in a bridge of the cord-circuit, the middle point of which bridge is connected with said battery, said relays being adapted to be operated over the grounded line conductors and corresponding strands of the cord-circuit when a connection is established, supervisory signals associated with said plugs and controlled by said relays, and circuit-breaking relays arranged to open the cord-strands and operated by either of the circuit-closing relays, whereby when a signal associated with one plug is operated the circuit-breaking relays are also operated to open the cord-strands.

14. In a telephone system, the combination with metallic telephone-lines, hook-switches at the substations connected in unvarying relation with one line conductor, signal-bells grounded by said hook-switches, a central office at which the lines terminate, individual signals at said office for said lines, a common battery to which said lines and signals are normally connected, an operators cord-circuit comprising plugs and strands between the tip of one plug and sleeve of the other, two circuit-closing relays in a bridge of the cord-circuit, the middle point of which bridge is connected With said battery, said relays being adapted to be operated over the grounded line conductors and corresponding strands of the cord-circuit when a connection is estab- Witnesses:

L. A. GARDINER, HARRY P. BAUMGARTNER. 

